The Murphy Builders Site

** Check your subject, does it still reflect the message? **

I cured high oil temps on my plane by moving the oil cooler to the rear
baffle ( check an early model cherokee for guidance ) Opening the cowl exit
by cutting it back about a foot on each side of the air box then riveting
new peices in shaped to increase the outlet hieght by about an inch and a
half. I also wrapped the exhaust with ceramic header tape from a speed shop
to cut down on heat off the exhaust. The biggest improvement was moving the
oil cooler.
My engine is an 0-290D and on the hottest days of summer on floats I see
oil temps around 190 degrees running at 2500rpm most of the time. In the
winter I have to fully block the oil cooler and I'm lucky if I can get up
to 160.

My Rebel ( read Bob Johnson's original #652 ) has taken to the air for
the first time from the water. Since we put the floats on I have had a
problem with high oil temps. They are running as high as 225 in climb
and even at 2200 rpm cruise they are around 215. With the floats you
expect higher temps because of the lower speeds and higher work load on
the engine but these are still too high running at 2300 rpm.OAT's were
running around 24 so not really hot - yet. I have an 0-320 H engine. All
lines to the oil cooler are good. We have checked the timing ( cause of
earlier high temps) and the oil temp guage itself. Both are fine.The
CHT's are running under 400 except for #2 which is running just over
400. EGT's are all close to 1200. Most 0-320 Cessna's use a 4" hose to
the cooler and GIWH has a 3". Also we may open up the bottom end of the
cowling to get more air flow. Any ideas?

Neil Hardie

Drew





-----------------------------------------------------------------
List archives located at: https://www.dcsol.com/login
username "rebel" password "builder"
Subscription services located at:
https://www.dcsol.com/public/code/html-subscribe.htm
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

Hi Drew !

Be very careful of that ceramic tape - especially if the exhaust
is not stainless steel !! There have been many reports of moisture
trapped in the tape causing hidden corrosion - one Rebel landed
with exhaust flames blowing out on the gascolator because the
whole pipe was eaten away under the tape !!

......bobp

Hi Bob
Thanks for the reminder. I know you don't like the stuff but I've been
flying with the tape on for over 6 years now. Neither the antique tri-pacer
crossover ehaust or the mild steel extension pipes were showing any signs
of deterioration other than surface rust on the mild steel last fall when I
checked. Were the ones that corroded stored outside?
Drew

Hi Drew !

Be very careful of that ceramic tape - especially if the exhaust
is not stainless steel !! There have been many reports of moisture
trapped in the tape causing hidden corrosion - one Rebel landed
with exhaust flames blowing out on the gascolator because the
whole pipe was eaten away under the tape !!

......bobp

Hi Drew !

That Rebel was stored in a hangar - albeit in a very foggy area -
Newfoundland ! ;-) :-) Maybe a little more humidity than your
area ...... It was just a reminder to peek under the tape now & then !
Sounds like you're having good results. Some builders have had
great results by having the insides of the exhaust pipes ceramic
coated - lots of automotive places to do this at reasonable cost...

.....bobp